Polyalkyldiazaspirodecanylacetic acid derivatives, a process for their preparation and their use as light stabilizers for organic polymers

ABSTRACT

New polyalkyldiazaspirodecanylacetic acid derivatives are prepared by reacting diazaspirodecanes of the formula ##STR1## in which X is ##STR2## with halogenoacetic acid derivatives, and, if desired, reacting products thus obtained further with alcohols or amines. The compounds can be used as light stabilizers for plastics and lacquers.

This application is a continuation of application Ser. No. 490,540 filedMay 2, 1983, which is now abandoned.

Numerous unsubstituted and substituted diazaspirodecanes of theoxazolidinone type are known from the literature. Thus, German Pat. Nos.2,606,026 and 2,634,957 describe compounds belonging to this class whichare not substituted on the oxazolidinone nitrogen and which aredistinguished by a quite good stabilizing effectiveness, but they alsosuffer, in some cases, from considerable disadvantages, especially inrespect of volatility and also inadequate solubility in some plastics.The result of this is that these products cannot be employeduniversally, i.e. not with equal success in several fields, such as, forexample, the paint sector and the plastics sector.

There has, therefore, been no lack of attempts to eliminate thesedisadvantages by enlarging the molecule or by means of substitution onthe polar NH group by alkyl radicals. Thus, European Pat. No. 17,617describes diazaspirodecanes which are substituted on the oxazolidinonenitrogen, but which are not technically satisfactory, particularlybecause of their excessive volatility. As opposed to this, theN-alkyldiazaspirodecanes which are known from German OffenlegungsschriftNo. 2,933,732 possess in some cases a remarkably low volatility, but canonly be prepared with difficulty and in an unsatisfactory yield.

The present invention is, therefore, based on the object of synthesizingdiazaspirodecane derivatives which have a good action and a lowvolatility and are thoroughly compatible with the polymers to bestabilized, importance being attached to high yields, as a furthercriterion.

It has been found that diazaspirodecanylacetic acid derivatives whichare accessible relatively easily and in good yields surprisingly fulfillthese requirements to a considerable extent.

The new compounds correspond to the general formula (I) ##STR3## inwhich X denotes a group of the formula (II) or (III) ##STR4## in whichthe indices 3 and 4 indicate the ring position in the diazaspirodecanesystem, and the free valency of the nitrogen atom 3 or 4 effects thelinkage with the acetic acid radical.

R¹ is hydrogen, oxygen or C₁ to C₁₂ alkyl, preferably hydrogen, oxygenor C₁ to C₄ alkyl and especially hydrogen, and R² is hydrogen or a C₁ toC₅ alkyl group, preferably hydrogen or a methyl group and, particularly,hydrogen.

R³ represents hydrogen, C₁ to C₃₀, preferably C₁ to C₁₈ and,particularly, C₁ to C₅, alkyl, a phenyl or naphthyl group which can bemonosubstituted or disubstituted by chlorine or C₁ to C₄ alkyl,preferably phenyl, or a C₇ to C₁₂ phenylalkyl group which can besubstituted by a C₁ to C₄ alkyl radical, preferably a benzyl group.

R⁴ denotes hydrogen, C₁ to C₃₀, preferably C₁ to C₁₈, and especially C₁to C₁₃, alkyl, phenyl or naphthyl which can be monosubstituted ordisubstituted by chlorine or C₁ to C₄ alkyl, preferably phenyl, or C₇ toC₁₂ phenylalkyl which can be substituted by a C₁ to C₄ alkyl radical,but preferably denotes benzyl.

R³ and R⁴, together with the carbon atom linking them, can alsorepresent a C₅ to C₁₈, preferably C₅ to C₁₂, cycloalkyl group which canbe substituted by up to four C₁ to C₄ alkyl groups, preferably methylgroups, or can represent a group of the formula ##STR5## n denotes aninteger from 1 to 6, preferably 1 to 4 and especially 1 to 3.

If n=1, R⁵ denotes hydrogen, C₁ to C₁₈, preferably C₁ to C₁₂, alkyl, C₇to C₉ phenylalkyl which can be monosubstituted or disubstituted by C₁ toC₄ alkyl, or C₃ to C₁₂ alkenyl, or represents a2,2,6,6-tetramethyl-4-piperidinyl group.

If n=2, R⁵ is a C₂ to C₃₀, preferably C₂ to C₁₈ and especially C₂ to C₆,alkylene group or a C₄ to C₈ alkenylene group or a C₂ to C₁₂bis-(propoxy)-alkylene group or a monocycloalkylene, dicycloalkylene ortricycloalkylene which has 6 to 18, preferably 6 to 12, carbon atoms andwhich can be substituted by up to four methyl groups, but is preferablynot substituted, it being possible, in the case first mentioned, for twocarbon atoms to be replaced by nitrogen atoms which can carry propylenegroups, or R⁵ is C₆ to C₁₈ arylene, preferably phenylene, or C₇ to C₁₈aralkylene.

If n=3, R⁵ is a C₃ to C₆ alkanetriyl radical or a radical of the formula##STR6## or a di-C₂ -alkylenetriamine to di-C₄ -alkylenetriamineradical.

If n=4 to 6, R⁵ is a C₄ to C₁₀ alkan-n-yl radical which can contain anether group, or is a tri-(C₂ to C₄) to penta-(C₂ to C₄) radical,preferably a tri-C₂ -alkylenetetra-bis-hexamine to penta-C₂-alkylenetetra-bis-hexamine radical.

Y represents --O-- or ##STR7## in which R⁶ has one of the meaningsindicated under R⁵ in the case where n=1.

The following are examples of polyalkyldiazaspirodecanylacetic acidderivatives according to the invention:

1. Ethyl2,2,7,7,9,9-hexamethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

2. Ethyl2,2,7,7,9,9-hexamethyl-1-oxa-4,8-diaza-3-oxospiro-[4,5]-decan-4-ylacetate

3.2,2,6,6-Tetramethyl-4-piperidinyl-2,2,7,7,9,9-hexamethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

4.Ethanebis-(2,2,7,7,9,9-hexamethyl-1-oxa-4,8-diaza-3-oxospiro-[4,5]-decan-4-yl)-acetamide

5. Ethyl7,7,9,9-tetramethyl-2,2-diethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

6.1,4-Butanebis-(7,7,9,9-tetramethl-2,2-diethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetate

7.1,6-Hexanebis-(7,7,9,9-tetramethyl-2,2-diethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetate

8.1,6-Hexanebis-(7,7,9,9-tetramethyl-2,2-diethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetamide

9.2,2,6,6-Tetramethyl-4-piperidinyl-7,7,9,9-tetramethyl-2,2-diethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

10. Methyl7,7,9,9-tetramethyl-2-ethyl-2-pentyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

11. Methyl2,7,7,9,9-pentamethyl-2-propyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

12. Methyl2,2,7,7,9,9-pentamethyl-2-undecyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

13. Methyl2,2,4,4-tetramethyl-10-tert.-butyl-7-oxa-3,13-diaza-14-oxodispiro-[5.1.4.2]-tetradecan-13-ylacetate

14.2,7,7,9,9-Pentamethyl-2-undecyl-1-oxo-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetamide

15. Glycolbis-(2,2,4,4-tetramethyl-10-tert.-butyl-7-oxa-3,13-diaza-14-oxodispiro-[5.1.4.2]-tetradecan-13-yl)acetate

16. Glycolbis-(2,7,7,9,9-pentamethyl-2-benzyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetate

17.7,7,9,9-Tetramethyl-2,2,-dibenzyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetamide

18.2,7,7,9,9-Pentamethyl-2-benzyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetamide

19. Ethyl7,7,9,9-tetramethyl-2,2-dibenzyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

20. Ethyl2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-ylacetate

21.2,2,6,6-Tetramethyl-4-piperidinyl-2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-ylacetate

22. Hexyl2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-ylacetate

23. 2-Ethylhexyl2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-ylacetate

24. Propanetriyltris-(2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-yl)-acetate

25. Hexanediylbis-(2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-yl)-acetate

26.1,6-Hexanebis-(2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[5.1.11.2]-heneicosan-20-ylacetamide

27. N,N'-3(4),8(9)-Bismethylenetricyclo-[5.2.1.0²,6]-decanebis-(2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxidispiro-[5.1.11.2]-heneicosan-20-yl)-acetamide

28. Propanetriyltris-(2,2,7,7,9,9-hexamethyl-1-oxa-4,8-diaza-3-oxospiro-[4,5]-decan-4-yl)-acetate

29. Tris-(1,3,5-triethylenetriazine-2,4,6-trione)2,2,7,7,9,9-hexamethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-ylacetate

30. N,N'-(3(4),8(9)-Bismethylenetricyclo-[5.2.1.0²,6]-decanebis-(2,2,7,7,9,9-hexamethyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]-decan-3-yl)-acetamide

31. Ethyl2,2,4,4-tetramethyl-7-oxa-3,13-diaza-14-oxodispiro-[5.1.4.2]-tetradecan-3-ylacetate

The new diazaspirodecanylacetic acid derivatives are prepared inaccordance with the diagram outlined below from the compounds of GermanPat. Nos. 2,606,026, 2,634,957 and 2,834,962 (IV) by reacting the latterwith halogenoacetic acid derivatives (V), either in a single processstage in accordance with route A or, in accordance with route B, frommethyl or ethyl esters (Ia) which have been obtained in accordance withroute A, by transesterifying the latter with alcoholic compounds oramidating them with compounds (VI) carrying amino groups. ##STR8##

In the formulae of the diagram of reactions, R¹, R², R³, R⁴, R⁵, n, Xand Y have the meanings indicated above; Hal is chlorine or bromine.

The detailed procedure followed in the preparation is first to preparethe corresponding salts from the diazaspirodecanes of the formula (IV)by reacting the latter with alkali metal hydrides, alcoholates orhydroxides, and then to react these salts in accordance with route A attemperatures of 100 to 200, preferably 120 to 200 and especially 140° to200, °C., in inert organic solvents, such as, for example, toluene,xylene or dimethylformamide, at ordinary pressure or under pressure,with halogenoacetic acid derivatives (V) to give the desired compoundsof the formula (I). It is also possible, and advantageous in many cases,to convert the methyl or ethyl esters (Ia), which can be obtained inaccordance with route A and which constitute a part of the invention,into other products according to the invention in accordance with routeB by transesterification or amidation. The latter reactions are carriedout at the reaction temperatures mentioned above, preferably in aromatichydrocarbons as solvents, with the addition of customary catalysts, suchas, for example, LiNH₂, NaOCH₃, Ti(O-i-prop)₄ and the like.

It was surprising and could not have been foreseen that thepolyalkyldiazaspirodecanylacetic acids according to the invention wouldbe markedly less volatile than the corresponding alkyl derivatives ofEuropean Pat. No. 17,617 or of German Offenlegungsschrift No. 2,933,732.It would rather have been expected that, owing to the similar molecularstructure, volatilities of a similar level would also have been observedat approximately equal molecular weights. Furthermore, it could in noway have been foreseen that the ester derivatives, in particular, wouldbe more suitable for stabilizing lacquers than the alkyl productsquoted, because of their similar polarity. All in all, therefore,technical advantages in use would not have been expected compared withthe compounds of the state of the art which have been quoted. The totalpattern of technical properties in use, which stands out in comparisonwith these compounds, must, therefore, be regarded as extremelysurprising.

The low volatility of the new products in which n=1 must also beespecially surprising to those skilled in the art. It is certainly knownfrom German Offenlegungsschrift No. 2,933,732 that alkylatedmonodiazaspirodecanes have quite a high volatility.

As already stated, the new compounds are used as stabilizes for plasticsto protect the latter against damage caused by the action of oxygen,heat and light. Examples of such plastics and of additives which canalso be employed additionally are mentioned on pages 14 to 19 of GermanOffenlegungsschrift No. 3,045,839.

The products according to the invention are particularly suitable forstabilizing homopolymers and copolymers of ethylene, propylene,butadiene, (meth)acrylic acid derivatives, particularly esters thereof,and styrene, in which cases they are generally employed in amounts of0.01 to 5, preferably 0.05 to 2.5 and particularly 0.1 to 1.0, % byweight, relative to the material to be stabilized--if appropriatetogether with other substances having a stabilizing action. The productsin which Y is --O-- are particularly suitable for stabilizing lacquersystems.

The examples which follow serve to illustrate the subject of theinvention in greater detail.

In the following preparation examples, the process products arecharacterized by numbers which relate to the numbering of the compoundslisted on pages 6, 7 and 8.

EXAMPLE 1 (compound No. 20)

109.2 g (0.3 mole) of dry2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxodispiro-[4,5]-heneicosane areinitially taken in 400 ml of anhydrous xylene. 9.0 g (0.3 mole) of 80%strength NaH/paraffin mixture are added and the mixture is heated toreflux temperature in the course of one hour, after which it is stirreduntil the evolution of hydrogen is complete (a further 3 hours). Themixture is then cooled to 20° C. and a solution of 50 ml of anhydrousxylene and 51.0 g (0.3 mole) of ethyl bromoacetate is added dropwise.The mixture is then stirred under reflux for 8 hours, then filteredwhile hot (38 g of NaBr), the filtrate is concentrated to dryness invacuo and the residue is recrystallized from n-heptane.

Yield: 119.8 g=88% of theory; melting point 154° C.

EXAMPLES 2 TO 18

The procedure employed is analogous to Example 1, using the spirodecanewhich can be derived in each case from the list of process products onpages 6, 7 and 8, and the halogenoacetic acid derivative specified inthe table below.

    ______________________________________                                        Exam-                    Process product                                      ple   Halogenoacetic acid                                                                              Compound                                             No.   derivative employed                                                                              No.       m.p. (°C.)                          ______________________________________                                        2     BrCH.sub.2 COOC.sub.2 H.sub.5                                                                    19        149                                        3     "                  30        91                                         4     "                   5        74-6                                       5     "                   1        83                                         6     "                   2        111                                        7     ClCH.sub.2 COOCH.sub.3                                                                           10        68                                         8     "                  11        86                                         9     "                  12        73                                         10    "                  13        114                                        11    ClCH.sub.2 CONH.sub.2                                                                            14        85                                         12    "                  17        233                                        13    "                  18        160                                        14                                                                                   ##STR9##           3        99                                         15    "                   9        92                                         16    "                  21        135                                        17    (ClCH.sub.2 COOCH.sub.2) .sub.2                                                                  15        154                                        18    "                  16        172                                        ______________________________________                                    

EXAMPLE 19 (compound No. 7)

27.5 g (0.077 mole) of compound No. 5 prepared in accordance withExample 4, 4.6 g (0.039 mole) of 1,6-hexanediol and 0.5 g of LiNH₂ in150 g of anhydrous mesitylene are stirred under reflux for 15 hours, inthe course of which 3.5 g of ethanol are removed by distillation througha 10 cm Vigreaux column. The mixture is then filtered while hot and thefiltrate is concentrated to dryness in vacuo. The oily product whichremains is crystallized from hexane.

Yield: 25.5 g=89% of theory; melting point 154° C.

MW: 715 (theory 734)

EXAMPLES 20 TO 31

The procedure is analogous to that of Example 19

    ______________________________________                                        Educts                                                                                                Educt                                                 Ex-                     (Ia)     Process product                              am-                     = com-   Com-                                         ple                     pound    pound  m.p.                                  No.  Alcohol or amine   No.      No.    (°C.)                          ______________________________________                                        20   2-Ethylhexanol     20       22     oil                                   21   n-Hexan-1-ol       20       23     oil                                   22   Glycerol           20       24     resin                                 23   1,6-Hexamethylenediamine                                                                          5        8     187                                   24   1,6-Hexanediol     20       25     68                                    25                                                                                  ##STR10##          1       30     105                                   26                                                                                  ##STR11##          1       29     90                                    27   Glycerol            2       28     86                                    28   as in Example 25   20       27     100                                   29   Ethylenediamine     2        4     248                                   30   1,6-Hexamethylenediamine                                                                         20       26     178                                   31   1,6-Hexanediol      5        7     77                                    ______________________________________                                    

EXAMPLE 32

This example demonstrates the volatility of the stabilizers according tothe invention, compared with products of the state of the art.

The volatility figures were determined in an apparatus forthermogravimetric analysis. Equal quantities (500 mg) of the stabilizersaccording to the invention and of the comparison substances were heatedto 300° C. in an atmosphere of nitrogen at a rate of heating of 2K/minute, and the loss of substance, in mg/cm² of sample surface, wasmeasured. The results are shown in the table below:

    ______________________________________                                        Stabilizer                                                                    according to                                                                             Loss of weight in mg/cm.sup.2 on reaching °C.               Example    220    260      300  10 minutes at 300                             ______________________________________                                        30         0.16   0.63     1.90 3.16                                           1         0.95   4.74     19.28                                                                              32.70                                         23         0.47   0.79     3.48 5.37                                          Comparison.sup.(1)                                                                       0.01   0.23     2.05 3.79                                          Comparison.sup.(2)                                                                       0.79   3.63     13.27                                                                              20.22                                         Comparison.sup.(3)                                                                       2.73   6.36     30.02                                                                              52.14                                         ______________________________________                                         .sup.(1) Compound according to Example 70 of German Auslegeschrift            2,933,732                                                                     .sup.(2) Compound according to Example 4 of German Auslegeschrift             2,933,732                                                                     .sup.(3) Compound according to Example 63 of German Auslegeschrift            2,933,732                                                                

EXAMPLE 33

A mixture, prepared in a laboratory high-speed mixer, of:

100 parts by weight of polypropylene (®Hostalen PPU VP 1770 F made byHoechst AG having a melt index MFI 190/5 of 1.9 g/10 minutes, determinedas specified in DIN 53,535),

0.2 part by weight of calcium stearate,

0.1 part by weight of pentaerythrityltetrakis-3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionate and

0.3 part by weight of the stabilizer to be tested, is converted intogranules. The material stabilized in this way is then melted in alaboratory extruder under the customary processing conditions and isspun into monofilaments via a spinning pump having an eight-orificespinning nozzle. These monofilaments are then subsequently stretched ina 1:3 ratio and are texturized to form yarn of 40 detex, which isconverted into test fabrics.

The fabric samples are mounted on a perforated piece of cardboard sothat a free aperture of approx. 15.5 mm diameter is left and aresubjected in this form to irradiation with alternating light in aXenotest X-1200 apparatus made by Original Hanau Quartzlampen GmbH. Theintensity of the radiation is modulated by a UV filter (special filterglass, d=1.7 mm), and the test method specified in DIN 53,387 (17minutes dry period, 3 minutes sprinkling, black panel temperature 45°C., relative atmospheric humidity during the drying period 70 to 75%) isused. At specific intervals of time the fabrics are loaded centrallyusing a weight of diameter 6 mm and a pressure of 0.1N/mm². The timewhen the weight breaks through is taken as the time of breakdown.

    ______________________________________                                        Stabilizer according                                                          to Example No.  Exposure time in hours                                        ______________________________________                                        23              900.sup.(X)                                                   24              900.sup.(X)                                                   Comparison.sup.(1)                                                                            900                                                           Comparison.sup.(2)                                                                            800                                                           ______________________________________                                         .sup.(1) Compound according to Example 70 of German Auslegeschrift            2,933,732                                                                     .sup.(2) Compound according to Example 4 of German Auslegeschrift             2,933,732                                                                     .sup.(X) Weight not yet broken through                                   

I claim:
 1. A polyalkyldiazaspirodecanylacetic acid derivative of thegeneral formula (I) ##STR12## in which X denotes a group of the formula(II) or (III) ##STR13## in which the indices 3 and 4 indicate the ringposition in the diazaspirodecane system, and the free valency of thenitrogen atom 3 or 4 effects the linkage with the acetic acid radical,R¹ is H, O or C₁ to C₁₂ alkyl, R² is H or a C₁ to C₅ alkyl group, R³ andR⁴ are identical or different and represent H, a C₁ to C₃₀ alkyl group,a phenyl or naphthyl group which can be substituted by chlorine or C₁ toC₄ alkyl, or a C₇ to C₁₂ phenylalkyl group which can be substituted byC₁ to C₄ alkyl, or R³ and R⁴, together with the carbon atom linkingthem, also denote a C₅ to C₁₈ cycloalkyl group which can be substitutedby up to four C₁ to C₄ alkyl groups, or a group of the formula ##STR14##n represents an integer from 1 to 6 and, if n=1, R⁵ denotes H, C₁ to C₁₈alkyl, C₃ to C₁₂ alkenyl, C₇ to C₉ phenylalkyl which can be substitutedby C₁ to C₄ alkyl, or a 2,2,6,6-tetramethyl-4-piperidinyl group, if n=2,R⁵ is C₂ to C₃₀ alkylene, a C₄ to C₈ alkenylene group, a C₂ to C₁₂bis-(propyleneoxy)-alkylene group or a monocycloalkylene,dicycloalkylene or tricycloalkylene which has 6 to 18 carbon atoms andwhich can be substituted by up to four methyl groups, it being possible,in the case first mentioned, for two carbon atoms to be replaced bynitrogen atoms which can carry propylene groups, or R⁵ is C₆ to C₁₈arylene or C₇ to C₁₈ aralkylene, if n=3, R⁵ denotes C₃ to C₆ alkanetriylor a radical of the formula ##STR15## or a di-C₂ -alkylenetriamino todi-C₄ -alkylenetriamino radical and, if n=4 to 6, R⁵ represents a C₄ toC₁₀ alkan-n-yl radical which can contain an ether group, or represents atri-C₂ to C₄ alkylenetetra-bis-hexamino to penta-C₂ to C₄-alkylenetetra-bis-hexamino radical, and Y is --O-- or ##STR16## inwhich R⁶ has one of the meanings indicated under R⁵ in the case wheren=1.
 2. A process for the preparation of a compound as claimed in claim1, which comprises converting an azaspirodecane of the formula (IV)##STR17## into an alkali metal salt thereof by reacting it with anequivalent quantity of an alkali metal hydride, alcoholate or hydroxidein an inert organic solvent at 50° to 160° C., and then reacting thissalt, at 100° to 200° C. in an inert organic solvent, with an equivalentquantity of a halogen compound of the formula (V) ##STR18## in whichHal=Cl or Br.
 3. The process as claimed in claim 2, wherein the alkalimetal salt of the compound (IV) is first reacted with a methyl or ethylhalogenoacetate, whereby a compound of the formula (I) in which n=1,Y=--O-- and R⁵ =CH₃ or C₂ H₅ is obtained, and this compound is thenreacted, in an inert organic solvent at 100° to 200° C., in the presenceof alkaline catalysts, with an equivalent quantity of a compound of theformula (VI)

    R.sup.5 (Y--H).sub.n                                       (VI)


4. A compound as claimed in claim 1 in which Y is --O--.
 5. A compoundas claimed in claim 1, wherein X denotes a group of said formula III. 6.A compound as claimed in claim 1, wherein Y is --N(R₆)--.
 7. A compoundas claimed in claim 1, wherein X denotes a group of said formula III,and Y is --N(R₆)--.
 8. A synthetic polymer which has been stabilizedagainst decomposition by ultraviolet light and which contains 0.01 to 5parts by weight, relative to the polymer, of a compound as claimed inclaim
 1. 9. An ultraviolet-stabilized synthetic polymer according toclaim 8, said polymer being a homopolymer or copolymer of ethylene,propylene, butadiene, acrylic acid or derivatives thereof, methacrylicacid or derivatives thereof, or styrene.
 10. An ultraviolet-stabilizedpolymer according to claim 9 which contains 0.05 to 2.5 percent byweight of the stabilizer compound wherein Y is --O--.
 11. A process forstabilizing synthetic polymers against the harmful effect of ultravioletlight, which comprises adding to the polymer 0.01 to 5 parts by weight,relative to the polymer, of a stabilizer as claimed in claim 1.